IUBMB Enzyme Nomenclature


Accepted name: cytokinin dehydrogenase

Reaction: N6-prenyladenine + acceptor + H2O = adenine + 3-methylbut-2-enal + reduced acceptor

Glossary: zeatin = (E)-2-methyl-4-(9H-purin-6-ylamino)but-2-en-1-ol = (E)-N6-(4-hydroxy-3-methylbut-2-enyl)adenine
prenyl = 3-methylbut-2-en-1-yl

Other name(s): N6-dimethylallyladenine:(acceptor) oxidoreductase; 6-N-dimethylallyladenine:acceptor oxidoreductase; OsCKX2; CKX; cytokinin oxidase/dehydrogenase

Systematic name: N6-prenylallyladenine:acceptor oxidoreductase

Comments: A flavoprotein(FAD). Catalyses the oxidation of cytokinins, a family of N6-substituted adenine derivatives that are plant hormones, where the substituent is a prenyl group. Although this activity was previously thought to be catalysed by a hydrogen-peroxide-forming oxidase, this enzyme does not require oxygen for activity and does not form hydrogen peroxide. 2,6-Dichloroindophenol, methylene blue, nitroblue tetrazolium, phenazine methosulfate and Cu(II) in the presence of imidazole can act as acceptors. This enzyme plays a part in regulating rice-grain production, with lower levels of the enzyme resulting in enhanced grain production [2].

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number: 55326-39-1


1. Galuszka, P., Frebort, I., Sebela, M., Jacobsen, S. and Pec, P. Cytokinin oxidase or dehydrogenase? Mechanism of cytokinin degradation in plants. Eur. J. Biochem. 268 (2001) 450-461. [PMID: 11168382]

2. Ashikari, M., Sakakibara, H., Lin, S., Yamamoto, T., Takashi, T., Nishimura, A., Angeles, E.R., Qian, Q., Kitano, H. and Matsuoka, M. Cytokinin oxidase regulates rice grain production. Science 309 (2005) 741-745. [PMID: 15976269]

[EC created 2001]

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